Russian Cosmonauts Complete 6-Hour ISS Spacewalk to Watch the Sun and Probe a Stuck Cargo-Ship Antenna

A longer-than-planned outing

Roscosmos cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev wrapped up a spacewalk outside the International Space Station at 4:23 p.m. EDT on Wednesday, logging 6 hours and 5 minutes of work, according to NASA. The excursion ran beyond its originally scheduled duration of roughly 5 hours as the pair worked through a packed list of objectives on the station's Russian segment, ranging from new-hardware installation to the retrieval of completed science experiments.

Watching the Sun

The headline task was the installation of a new instrument on the Zvezda service module designed to measure bursts of solar radiation from solar flares. Space-weather monitoring of this kind has real consequences on Earth: intense solar activity can disrupt satellites, degrade navigation signals and, in extreme cases, stress electrical grids. Mounting the detector on the station's exterior gives researchers a continuous vantage point above the protective layers of the atmosphere.

Bringing experiments home

The cosmonauts also removed a microorganism study that had been mounted on the exterior of the Poisk module, part of long-running research into how living organisms cope with the extremes of open space, including vacuum, radiation and temperature swings. They additionally retrieved a cassette from the Nauka module containing data on how semiconductor materials form in microgravity. Because gravity influences how such materials crystallise, studying their formation in orbit could inform the manufacture of higher-quality electronic components.

A cargo-ship mystery

During the spacewalk, the pair photographed one of two Kurs rendezvous antennas on the Progress 94 cargo spacecraft that failed to deploy after its March launch. After collecting imagery for engineers on the ground to analyse, they secured the antenna with a tie-down so it stays stable during future dynamic operations such as docking and undocking.

Career milestones

The outing marked the second spacewalk for Kud-Sverchkov, who has now accumulated 12 hours and 11 minutes of extravehicular activity, and the very first for Mikaev. It was the 279th spacewalk in support of station assembly, maintenance and upgrades since construction began in 1998. The activity was part of the ongoing Expedition 74, with Kud-Sverchkov serving as commander and Mikaev as flight engineer. NASA provided live coverage of the event beginning at 9:45 a.m. EDT, and both crew members returned safely inside the station after completing every assigned task.